UCLA researchers study social forces shaping human behavior during war

The wife-and-husband team digs into the details of 41,000 Civil War soldiers for a book exploring why some soldiers desert while others stay and fight.

What makes one soldier stay and fight on a battlefield and another desert and flee?

That question intrigued Dora L. Costa and Matthew E. Kahn, a wife-and-husband research team of UCLA economists who dug into the details of 41,000 Civil War soldiers' lives for an unusual look at the social forces shaping human behavior during conflict. The result is their book "Heroes and Cowards: The Social Face of War."

The book's thesis is that serving in a homogenous Army company, particularly one of volunteers recruited from the same hometown region, reduced desertion rates significantly in the 1860s. Patriotism played a role in keeping soldiers at the fronts, but more important factors were sticking with buddies of similar immigrant and economic backgrounds and avoiding a bad reputation back home, the book posits.

"Loyalty to comrades trumped cause, morale and leadership. But loyalty to comrades extended only to men like themselves -- in ethnicity, social status and age," the authors wrote.

During a recent interview in Costa's office at UCLA, the couple talked about the potential relevance of their research to the U.S. military operations in Iraq and Afghanistan.

Unlike the Civil War army, American units today are ethnically and geographically diverse. Yet the military has learned to reinforce the bonds gained in training, and usually rotates entire units in and out of war zones rather than fill in for casualties with new soldiers as it did during the Vietnam War, the professors said.

Their conclusions about the Civil War may not seem surprising, but the research behind it is. They used Internet databases as well as copies of antique paper documents in the elegant cursive penmanship of 19th century government clerks. They applied the statistical tools of economic analysis to history, a cross-disciplinary technique increasingly popular in academia.

Costa and Kahn tapped into computerized Civil War records previously collected by a multi-university research team with funding from the National Institutes of Health. That team was led by Nobel Prize laureate Robert Fogel, who was Costa's doctoral advisor at the University of Chicago. (Kahn also earned his doctorate in economics at the University of Chicago and the couple met there. Married in 1998, they have a 7-year-old son, Alexander, to whom the book is dedicated.)

Through those archives, the authors examined service records, ages, birthplaces, pre-war occupations, battlefield deaths and prisoner of war interments among 35,000 white and 6,000 black Union soldiers. They also tracked census and pension information going back in some cases to 1850 and as far forward as 1910. (Similar Confederate records were not available, they said.) And to estimate pro-Union sentiment among the troops they studied, the researchers examined support for President Lincoln's presidential elections in the soldiers' home counties.

Costa described those Union army records as a treasure trove that allows insights into "individuals who might have not left any other record." In addition, she said, it is "a fantastic laboratory for studying how do men behave under extreme stress."

The couple said they were partly inspired by Harvard University professor Robert D. Putnam's 2000 book "Bowling Alone: the Collapse and Revival of American Community."

"We wanted to look at more high-stakes outcomes, such as deserting and ditching your buddies or surviving POW camps. War is a high-stakes laboratory, and we agreed we could come back to some of Robert Putnam's ideas about cohesion and being a civically engaged citizen, but in a setting of a life-and-death war," Kahn said.

Their research found that the average Union desertion rate was about 10%. "Given the horrific conditions, it is surprising there was so little desertion," Costa said.

That was especially true since fewer than half of those who deserted were caught, punishment often was not very harsh and execution extremely rare, according to the book.

"Heroes and Cowards," published by Princeton University Press, delves into different Army units' social composition and desertion experiences. Through complicated statistical analysis, the authors developed a formula in which group loyalty in the Union regiments was found to have counted twice as much in preventing desertion as a soldier's ideology and six times as much as their unit leaders' popularity.

For example, Company D of the 36th Regiment contained many neighbors and relatives from Worcester County, Mass. The men, mainly mechanics and artisans in prewar life, saw heavy action and no desertions. In contrast, Company B of the 47th Regiment from New York was more diverse, with men from cities and farms, as well as laborers who were paid to substitute for conscripts. Its desertion rate was 16%.